www.nature.com/scientificreports
OPEN
received: 07 October 2014 accepted: 20 March 2015 Published: 22 May 2015
The proto-oncogene survivin splice variant 2B is induced by PDGF and leads to cell proliferation in rheumatoid arthritis fibroblast-like synoviocytes Sho Mokuda1, 2, 3, 4, Tatsuhiko Miyazaki3, Yuki Ito3, Satoshi Yamasaki4, Hiroko Inoue1, Yun Guo1, Weng-Sheng Kong1, Masamoto Kanno1, Kiyoshi Takasugi2, Eiji Sugiyama4 & Junya Masumoto3 Survivin is an independent prognostic factor for joint destruction in rheumatoid arthritis (RA). However, the expression and function of survivin in RA synoviocytes remain unclear. We certified the expression of survivin in RA synovial tissues and performed the experiment using RA fibroblastlike synoviocytes (RA-FLS) treated with siRNA. As a result, the expression levels of wild type (WT) survivin and the 2B splice variants in RA synovial tissues were higher than those in osteoarthritis tissue samples, and, these variants were highly expressed in RA-FLS. The expression levels of survivin-WT and -2B in the RA-FLS were upregulated by PDGF. Treatment with siRNA against survivin-2B led to decreased viability of PDGF-treated RA-FLS due to cell cycle suppression and apoptosis promotion, while the siRNA against all survivin isoforms did not affect the viability. Moreover, an overexpression of survivin-2B in RA-FLS led to cell proliferation through cell cycle activation and by conferring resistance to apoptosis. In conclusion, survivin-2B has an important role in RA-FLS proliferation. These data suggest that survivin-2B might contribute to rheumatoid synovial hyperplasia, and have the potential as a novel therapeutic target for RA.
Rheumatoid arthritis (RA) is a chronic inflammatory disease characterized by hyperplastic synovial tissue and destruction of articular cartilage and adjacent bone1. The proliferative synovial tissues from RA patients consist of mainly of synoviocytes, capillary vessels and infiltrated lymphocytes. The cartilage destruction is caused by matrix metalloproteinase, which is produced by fibroblast-like synoviocytes (FLS)2. The bone destruction (bone erosion) in RA results from osteoclast-mediated bone resorption activated by RANKL, produced by FLS and T lymphocytes3,4. Therefore, FLS are major effector cells involved in RA synovitis. Moreover, RA-FLS exhibit pre-neoplastic characteristics. Several reports have indicated that RA synovitis might be characterized by elevated expression of proto-oncogene proteins in the FLS (for example, c-Myc, Ras, c-fos and p53 mutants)5–10. Proto-oncogene survivin is a member of the IAP (inhibitor-of-apoptosis) family of proteins. It is encoded by the BIRC5 gene located on human chromosome 17q25, and is a 142 amino acid, 16.5 kDa, protein, which contains a single BIR (baculovirus iap repeat) domain and a coiled-coil α-helix domain11. 1
Department of Immunology, Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan. 2Department of Internal Medicine, Center for Rheumatic Diseases, Dohgo Spa Hospital, Matsuyama, Japan. 3 Department of Pathology, Ehime University Proteo-Science Centre and Graduate School of Medicine, Toon, Japan. 4Department of Clinical Immunology and Rheumatology, Hiroshima University Hospital, Hiroshima, Japan. Correspondence and requests for materials should be addressed to S.M. (email: [email protected]) Scientific Reports | 5:09795 | DOI: 10.1038/srep09795
1
www.nature.com/scientificreports/
Figure 1. The survivin expression in blood and synovial tissues from RA and OA patients. (a) The serum survivin expression levels were analyzed using an ELISA. (RA, 22 cases; controls, 16 cases) (mean RA, 19.5 pg/ml vs. controls, 7.7 pg/ml; p = 0.044). An age- and sex-matched control group consisted of OA and healthy controls (RA, 58.8 ± 15.6 years old; controls, 53.9 ± 19.8 years old; p = 0.404). t-test, *p
OPEN
received: 07 October 2014 accepted: 20 March 2015 Published: 22 May 2015
The proto-oncogene survivin splice variant 2B is induced by PDGF and leads to cell proliferation in rheumatoid arthritis fibroblast-like synoviocytes Sho Mokuda1, 2, 3, 4, Tatsuhiko Miyazaki3, Yuki Ito3, Satoshi Yamasaki4, Hiroko Inoue1, Yun Guo1, Weng-Sheng Kong1, Masamoto Kanno1, Kiyoshi Takasugi2, Eiji Sugiyama4 & Junya Masumoto3 Survivin is an independent prognostic factor for joint destruction in rheumatoid arthritis (RA). However, the expression and function of survivin in RA synoviocytes remain unclear. We certified the expression of survivin in RA synovial tissues and performed the experiment using RA fibroblastlike synoviocytes (RA-FLS) treated with siRNA. As a result, the expression levels of wild type (WT) survivin and the 2B splice variants in RA synovial tissues were higher than those in osteoarthritis tissue samples, and, these variants were highly expressed in RA-FLS. The expression levels of survivin-WT and -2B in the RA-FLS were upregulated by PDGF. Treatment with siRNA against survivin-2B led to decreased viability of PDGF-treated RA-FLS due to cell cycle suppression and apoptosis promotion, while the siRNA against all survivin isoforms did not affect the viability. Moreover, an overexpression of survivin-2B in RA-FLS led to cell proliferation through cell cycle activation and by conferring resistance to apoptosis. In conclusion, survivin-2B has an important role in RA-FLS proliferation. These data suggest that survivin-2B might contribute to rheumatoid synovial hyperplasia, and have the potential as a novel therapeutic target for RA.
Rheumatoid arthritis (RA) is a chronic inflammatory disease characterized by hyperplastic synovial tissue and destruction of articular cartilage and adjacent bone1. The proliferative synovial tissues from RA patients consist of mainly of synoviocytes, capillary vessels and infiltrated lymphocytes. The cartilage destruction is caused by matrix metalloproteinase, which is produced by fibroblast-like synoviocytes (FLS)2. The bone destruction (bone erosion) in RA results from osteoclast-mediated bone resorption activated by RANKL, produced by FLS and T lymphocytes3,4. Therefore, FLS are major effector cells involved in RA synovitis. Moreover, RA-FLS exhibit pre-neoplastic characteristics. Several reports have indicated that RA synovitis might be characterized by elevated expression of proto-oncogene proteins in the FLS (for example, c-Myc, Ras, c-fos and p53 mutants)5–10. Proto-oncogene survivin is a member of the IAP (inhibitor-of-apoptosis) family of proteins. It is encoded by the BIRC5 gene located on human chromosome 17q25, and is a 142 amino acid, 16.5 kDa, protein, which contains a single BIR (baculovirus iap repeat) domain and a coiled-coil α-helix domain11. 1
Department of Immunology, Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan. 2Department of Internal Medicine, Center for Rheumatic Diseases, Dohgo Spa Hospital, Matsuyama, Japan. 3 Department of Pathology, Ehime University Proteo-Science Centre and Graduate School of Medicine, Toon, Japan. 4Department of Clinical Immunology and Rheumatology, Hiroshima University Hospital, Hiroshima, Japan. Correspondence and requests for materials should be addressed to S.M. (email: [email protected]) Scientific Reports | 5:09795 | DOI: 10.1038/srep09795
1
www.nature.com/scientificreports/
Figure 1. The survivin expression in blood and synovial tissues from RA and OA patients. (a) The serum survivin expression levels were analyzed using an ELISA. (RA, 22 cases; controls, 16 cases) (mean RA, 19.5 pg/ml vs. controls, 7.7 pg/ml; p = 0.044). An age- and sex-matched control group consisted of OA and healthy controls (RA, 58.8 ± 15.6 years old; controls, 53.9 ± 19.8 years old; p = 0.404). t-test, *p
